The invention concerns a still photo camera, and in particular a still photo camera adapted to use film and electronic media.
Still photo cameras are known which use various recording media. Some still cameras use conventional film materials, i.e., chemical image recording. Others use electronic image recording, i.e., photoelectric converters, electronic signal processing and electronic signal storage. Still cameras that use more than one medium are difficult to handle and flexibility when switching from one to the other is limited.
The invention has the goal of significantly increasing the handling flexibility when changing from photography with conventional film material to photography with electronic image recording
This goal is achieved in a still photo camera which is characterized by the features of claim 1, which according thereto proposes the inclusion in one and the same still photo camera film for chemical image recording and an electronic arrangement for electronic image recording, to be selected as desired. With respect to image evaluation which concerns image composition, image detail, depth of sharpness, entry of light, the invention further proposes the provision of an adjusting disk. In an exemplary embodiment the particular image disk is in the form of a ground glass disk. The adjusting disk may be inserted into the image beam path. The adjusting or image evaluation disk is introduced into the focal plane. The adjusting disk may be movably positionable in a spring loaded support, so that, when positioned in the image beam path of the camera, it may be pushed behind the focal plane during emplacement of the film media or the electronic image recording media.
The camera, film and electronic arrangement may be constructed using an adapter or intermediate parts, so that a film cassette for the film or the electronic arrangement can be mounted on the camera housing if desired. Alternatively, a coupler device which can move linearly or by a swinging action may be employed. The coupler has a receptacle for the film and a receptacle for the electronic arrangement. If necessary, the camera may employ another receptacle for the adjusting disk. Using the coupler device, the desired receptacle is selected and moved into the image beam path of the camera.
During image recording the exposure time is adapted to the medium, in particular for film but also if necessary for the electronic arrangement, according to the appropriate sensitivity of the selected recording medium and the light intensity.
In an exemplary embodiment of the invention, the electronic arrangement may include a monochrome arrangement or multi-chrome arrangement, or both. These arrangements may also employ a charge coupled device (CCD) and, if desired, a mosaic filter. If both arrangements for electronic image recording are provided, the flexibility of the camera will be further increased in that a rapid change can be made from electronic monochrome recording to electronic multi-chrome recording.
If a monochrome arrangement is provided for electronic image recording with or without a multi-chrome arrangement, a filter arrangement with a number of selectable narrow band color filters may be used. The filters may be introduced, when desired, into the image beam path, by, for example, a motor provided on the camera. In an exemplary embodiment, the lens may be interchangeable and the filters may be introduced between the interchangeable lens and the focal plane. For additive processes, one each of a red, green and blue (RGB) filter may be employed as the narrow band color filters. For color printing in subtraction processes, cyan, magenta, yellow and black (CMYK) filters may be employed.
When the color filters are positioned in the lens screen area or in front of the lens, no increase of the focus will occur as a result. However, if as preferred, a compact and easy to handle component camera system is desired, the color filter arrangement is placed between the interchangeable lens and the focal plane where the monochrome CCD arrangement may be moved. As a result the filters cause an increase of focus corresponding to the following relationship:
xcex94f=dxc3x97nxe2x88x92l/n
where
d=filter glass thickness, and
n=refractive index of the filter glass material.
During the evaluation operation, this may be accounted for in a simple manner by introducing into the image beam path a passive image evaluation disk such as a broad band, white-light-transmitting disk with appropriate thickness and an appropriate refractive index that simulates the focal relationships of the color filter that are to be later employed.
In place of, or in addition to, the passive image evaluation disk, an active device such as a photoelectric converter arrangement with a live image display screen or with a connection for an external display may be provided.
During active image evaluation using a CCD and by means of a live image display, the image is optically scrambled with a given frequency of two to five Hz. This may be accomplished by means of an electronic connection which may also be provided to the mechanical camera shutter. In an exemplary embodiment optical scrambling is achieved by means of an LCD shutter driven with clock pulses. In such arrangement the electronic shutter, for example, the LCD shutter with color filters, may cause lengthening of the focus. Since the LCD shutter is only positioned in the image evaluation mode and the color filters normally only in the image recording mode by means of the monochrome arrangement, the LCD shutter compensates for the lengthening of focus caused by the filters.
By providing a multi-chrome arrangement for the electronic image recording, for example, a CCD arrangement with mosaic filters, the focal length relationships may be taken into consideration during assembly or insertion of the above-mentioned arrangement by appropriate staggering of the depth of the focal plane on the slide.
During image recording with a multi-chrome arrangement for electronic image recording, the focal length change is compensated for by a broad-band, transmitting disk in the image recording mode and by the LCD shutter in the image evaluation mode.
In order to ensure the highest possible degree of compactness in the camera, the color filters, the broad-band transmitting disk, the LCD shutter and one or more open screen segments may be mounted on one or more motor-driven carrier wheels. An exemplary embodiment employs two separate, independent, adjustable carrier wheels.
The image evaluation may be conducted using an adjusting disk, or an electronic image acquisition arrangement, at times equipped with a live image display. The actual image recording may be made on film or electronically. Appropriate optical devices are inserted for the image evaluation mode and the image recording mode. This may be accomplished automatically by means of an input device for selecting in the image evaluation mode, an adjusting disk, or an electronic image acquisition arrangement and possibly sensors for the acquisition of the current input image evaluation medium. Other input devices may be employed for automatic selection of the image recording medium, the automatic electronic shutter, the broad-band filter compensating disk, the color filters, and the open screen elements, as required in accordance with the selected image evaluation medium and image recording medium.